Narrow Line Seyfert 1 galaxies in the context of Quasar Main Sequence

NLS1 galaxies are considered to be high Eddington ratio sources. But in the context of Quasar Main Sequence, high Eddington rate sources are those which have weak [OIII] lines and strong Fe II lines. There is an overlap between the two populations, but they are not identical. I will discuss this issue from the point of view of the broad band SED, emission line shape modelling, Fe II pseudo-continuum strength, and the level of X-ray variability. I will also discuss the issue of the viewing angle and the insight we gain from spectro-polarimetric observations.